The steadily shrinking polar ice cap, melting permafrost and disappearing animals are part of the problem. But scant weather stations, inaccessibility and difficult conditions have put off data collection for decades.

"I believe it's crucial that we do that," said Dan Goldin, head of the National Aeronautics and Space Administration. "We at the federal agencies need to look at changing our priorities and put more of an emphasis here."

Goldin and other panelists discussed climatic changes and their impacts on the arctic at a Fairbanks hearing of the Senate Appropriations Committee, chaired by U.S. Sen. Ted Stevens, an Alaska Republican.

Villagers along the Arctic Ocean see evidence of climate change every day, said Caleb Pungowiyi, president of a nonprofit foundation established by NANA Regional Corp.

The sky isn't as blue as it used to be, obscured frequently by a strange white haze, he said. The shrinking ice cap is forcing marine mammals and other sea life away from shore, so hunters must travel farther. Because the protective pack ice forms later and softer, storms that batter the coast eat great chunks of land away around Barrow and the villages of Kivalina, Point Hope and Shishmaref.

"These are changes that have gone unnoticed by the policy-makers and scientists," Pungowiyi said.

Several researchers said current climate changes likely stem from a combination of factors including natural variation and human activity.

"We don't know whether this change is part of a cycle or is following a long-term, possibly irreversible trend," said Rita Colwell, director of the National Science Foundation.